Knitting machine improvement



C. R. MASTERS KNITTING MACHINE IMPROVEMENT May 12, 1970 Filed April 24. 1967 5 sheets-sheet].

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CHARLES R. MASTERS ATTORNEY United States Patent Office 3,511,063 Patented May 12, 1970 3,511,063 KNITTING MACHINE IMPROVEMENT Charles R. Masters, Pickens, S.C., assignor to Deering Milliken Research Corporation, Spartanburg, S.C., a

corporation of Delaware Filed Apr. 24, 1967, Ser. No. 633,210 Int. Cl. D04b 27/22 U.S. CI. 66-86 12 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus to automatically adjust the speed of the warp beam of a fabric producing machine by comparing a length of yarn being supplied to the machine to a standard length and automatically adjusting the speed of the warp beam if the compared length of yarn is shorter than the standard.

This invention relates generally to fabric producing machines such as looms, knitting machines, etc., and more particularly to an electronic sensing device which automatically adjusts the let-off of a knitting machine.

In most fabric producing machines the warp beam which supplies the yarn to be made into fabric is driven at a substantially constant speed relative to the speed of the fabric producing machine. This necessitates close observation of the machine by an operator since after each rotation of the warp beam the diameter of the yarn thereon being supplied to the fabric producing machine is less than the previous diameter. Therefore, the speed of the warp beam has to be periodically increased in order to maintain the supply of the correct amount of yarn to the fabric producing machine. In the past, this correction has normally been made manually by an operator after visual inspection of the machine.

The above-mentioned problem is especially critical in the knitting of elastic fabrics since slight variation in the width of the fabric causes the fabric to be graded as see onds. It can be seen that an operator cannot accurately and consistently adjust the speed of the warp beam since the observation of the machine is visual and the operator may not be present at the correct time for such adjustment since one operator works on more than one machine.

It is therefore an object of the invention to provide automatic adjustment of the speed of the yarn supplying beam of a fabric producing machine.

Another object of the invention is to provdie an automatic adjustment of the let-off of a knitting machine in response to the length of yarn being supplied to the needles thereof.

A still further object of the invention is to provide for automatic electronic adjustment of the let-off of a knitting machine in response to the length of elastic yarn being supplied to the needles thereof.

A fourth object of the invention is to provide a more eflicient fabric producing machine which does not require the constant attention of an operator.

Other objects and advantages will be clearly apparent as the specification proceeds to describe the invention with reference to the accompanying drawings, in which:

FIG. 1 is a front elevation partially schematic view of a knitting machine;

FIG. 2 is a right hand schematic elevation view of the knitting machine shown in FIG. 1;

FIG. 3 is a partial view of the yarn measuring mechamsm;

FIG. 4 is a circuit diagram of the warp beam speed adjusting mechanism; and

FIG. 5 is a modification of the yarn comparing apparatus shown in FIGS. 1-4.

The specific disclosed embodiment is directed to a warp knitting machine producing elastic fabrics but obviously the disclosed invention is applicable to any fabric producing machine in which it is necessary to maintain the supply of a constant length of yarn to the fabric producing elements of the machine.

In warp knitting machines, especially machines producing elastic fabric, it is necessary to maintain a constant supply of a desired predetermined length of yarn during each cycle or rack of the machine. The usual, but not by any means the only, cycle in such machines is one consisting of four hundred eighty courses of fabric and is generally referred to as a rack. Therefore, for the purpose of illustration the length of yarn for one rack is used as a standard.

Looking now to FIGS. 1 and 2. a conventional warp knitting machine 10 is shown modified in a manner hereinafter described. In conventional manner warp yarn 12 is supplied to needle bar 14 for knitting into knit fabric 16 from warp beam 18 successively over guide bars 20, 22, 24 and 26. The knit fabric 16 is delivered from needle bar 14 to the cloth roll 28 by the take-up rolls 30 driven in conventional manner.

Looking at FIG. 2 the knitting operation is only schematically represented since the particular knitting operation is not part of the invention. Knitting bars 32 actuated through suitable linkage (not shown) cooperates with needle bar 14 to form the knitted fabric 16. Needle bar 14 is carried in arms 34 which are fastened in a rocker arm 36. Needle bar 14 is driven by pushrod 38 which is connected to lever 40 pivotally connected to eccentric 42 driven by shaft 44 connected to the main drive 46 through a chain member 48.

The warp beam 18 is rotatably supported on shaft 48 which is driven by worm gears (not shown) in gear box 50. The drive for the gear box 50 is from main drive 52 through the variable speed drive composed of cone 54 which drives another cone 56 through the medium of ring 58 which determines the speed of shaft 60 connected to the gear box 50. Connected to ring 58 is a sliding forked member 62 rigidly connected to shaft member 64 and having fitted therein a portion of ring 58. Shaft member 64 in turn is connected to pivotally mounted lever arm 66 the position of which is controlled by controller 68 in a manner hereinafter explained. Controller 68 can be a stepping motor or any other suitable actuator. Warp beam main drive 52 can be suitably geared to drive motor 46 or be a separate drive member.

As previously discussed the preferred standard of yarn length is the amount of yarn required to knit four hundred eighty courses of fabric. This distance (FIG. 1) is represented by the distance between the centerline 70 of the conducting tint solution applicator 72 and point just to the left of sensing grid 74. Mounted on the knitting machine is a rotatably supported rod member 76 to which is connected to a plurality of collar members 78. Inserted in and connected to each of the collar members is an L-shaped rod member 80 which, when the rod 76 is rotated clockwise, will engage and depress the yarn '82 down on the tint solution applicator 72 and in between the grids 84 of the sensing grid 74. Mounted on the knitting machine is a solenoid actuator 86 having a plunger rod 88 to which is connected lever 90. Lever arm 90 is rigidly connected to rod member 76 and rotates rod member 76 clockwise when the solenoid actuator 86 is energized and rotates the rod member 76 counterclockwise when the solenoid actuator 86 is de-energized. The solenoid actuator is electrically and/or mechanically interconnected with the knitting machine drive so that it is actuated every time when the knitting machine has theoretically knit four hundred eighty courses of yarn. In other words, based on the speed of the knitting machine, the amount of yarn necessary to knit four hundred eighty courses of yarn under predetermined tension can be calculated. This calculation is used to determine the actuation of the solenoid actuator 86 to compare theactual length of yarn being taken by the knitting against the amount that should be taken. The result of this comparison is used to adjust the speed of the warp beam 18.

When the knitting machine is threaded up one warp end will be supplied from the warp beam 18, down through a pig tail guide 92, across the width of the knitting machine, through another pig tail guide 94 and to the needles of the machine. Solenoid actuator 86 is energized every time the knitting machine indicates when four hundred eighty courses should have been knit. The rod member 76 will then be rotated clockwise by the action of the plunger on the lever 90 to cause the yarn 82 to assume the position indicated in FIG. 3 with one portion of the yarn on the wick 96 of the conducting tint solution applicator 72 and another portion of the yarn 82 between the grids 84 of the sensing grid 74. Preferably the solution in the applicator 72 is one containing a dye and an electrolytic salt so that the portion touching the wick 96 will be dyed and also be conductive. The action of the solenoid actuator is only momentary and the solenoid will then be de-energized and the yarn will be let up and travel toward the sensing grid 74.

As discussed previously the basic problem confronted is that the amount of yarn being supplied to the knitting needles, if not compensated for, would be shorter and shorter since the warp beam 18 and the knitting machine operates at constant speed and the length of each diameter of yarn unrolled from the warp beam is shorter than the previous diameter of yarn unrolled from the warp beam. This continuous decrease in length of the yarn being supplied will increase the tension in such yarn and in the knitting of elastic fabrics will cause distortion in the width thereof resulting in second quality goods being manufactured, if not compensated for. Therefore, based on the speed of the knitting machine, the distance between the centerline 70 of the conducting tint solution applicator 72 and a point just beyond the sensing guide 74 is the distance required for the theoretical length of yarn to travel the four hundred eighty courses.

After the conductive tint has been applied to the yarn 82, the yarn 82 will travel toward the pig tail guide 94. When the yarn 82 reaches the sensing grid 74 the solenoid actuator will again be energized and the yarn will be pushed down on the wick 96 and between the grids 84. If the previously tinted portion of the yarn falls outside the grids 84 it can be seen that nothing will occur but if the conductive tinted portion of the yarn falls in the middle of the grid area the circuit will be completed to controller 68 through amplifier 98 (manual on-off switch 100 being closed). When the controller 68 is pulsed the lever arm will be moved to the right causing ring 58 to move to the right thereby automatically increasing the speed of cone 56 and thusly increasing the speed of the warp beam 18.

As previously pointed out the energization of the solenoid actuator 86 is momentary so that the change in the speed of the warp beam 18 at any one time is very slight. The measurement of the yarn 82 is automatic and continuous to provide constant automatic speed adjustment of the warp beam eliminating constant supervision by an operator. Furthermore, the conductive tint which includes a dye provides a means of visual inspection to check to see if the sensing grid is properly adjusting the speed of the warp beam when necessary.

Looking now to the modification shown in FIG. 5 a different system is illustrated to perform the same desired result. In the modification of FIG. 5 freely rotatable rollers 102 and 104 are mounted on the frame of the knitting machine. Warp end 82 from the warp beam 18 is wrapped around the roll 104 and then is directed to roll 102 around which it is also wrapped. From the roll 104 it is supplied to the knitting machine. Mounted on the rolls'102 and 104 under the rod members and rotating with said rolls is an endless band 106, preferably of paper, equivalent in length to the length of yarn knit in one cycle or rack of the knitting machine. A small piece of foil or conductive material 108 is placed on' the appropriate posi tion so that when solenoid 86 actuates the rod members 80 will rotate against the band 106 causing the band to assume the position assumed by the yarn 82 in FIGS. 1-4 thereby placing the conductive material 108 in the same relative position as the tint mark of FIGS. 1-4.

In operation, the warp yarn 82 in passing over the freely rotatably mounted rolls 102 and 104 causes rolls 102 and 104 to rotate therewith and in turn causing band 106 to rotate also. As in FIGS. 1-4 the rod members 80 will be periodical y rotated against the band 106 forcing it down into the grid member 74. If the conductive material 108 falls within the confines of the grid the controller 68 will be actuated to increase the speed of the warp beam 18 in the manner previously described.

Although I have described in detail the preferred embodiment of my invention I contemplate that many changes may be made without departing from the scope or spirit of my invention, and I desire to be limited only by the claims.

That which is claimed is:

1. A method of producing a knit fabric comprising the steps of: supplying Warp yarns to a plurality of knitting needles at a substantially constant speed, knitting said Warp yarns into a knit fabric, rolling up said knit fabric, comparing a portion of a substantially straight length of at least one of said warp yarns to a predetermined standard length to detect a warp yarn of a length less than the standard length, detecting a warp yarn shorter than the standard length and automatically adjusting the speed of supply of said warp yarns upon the detection of a warp yarn of less than the standard length.

2. The method of claim 1 wherein the step of comparing a portion of the length of said warp yarn is continuous throughout the knitting operation.

3. Apparatus to produce a fabric having a warp yarn comprising: a fabric producing machine, means supplying Warp yarns to said machine at a constant speed, means to compare a substantially straight length of one of said Warp yarns to a standard length and to detect a warp yarn shorter than said standard length and means responsive to the detection of a warp yarn shorter than a standard length to automatically adjust the speed of said warp yarn supply means.

4. The structure of claim 3 wherein said one of said warp yarns is guided in a predetermined path prior to being produced in a fabric, said means to adjust the speed of said warp yarn supply means including an applicator means to apply a substance to a portion of said one warp yarn and a detecting means spaced downstream from applicator means to detect said substance.

5. The structure of claim 4 wherein said substance includes a conductive material and said detecting means includes a sensing grid. 7

6. The structure of claim 5 wherein said adjusting means includes a means to periodically depress said one warp end down onto said applicator means and said dedecting means.

7. An improved warp knitting machine comprising: a warp beam having warp yarn thereon, a plurality of knitting needles, means rotating said warp beam at a constant speedto deliver warp yarn to said knitting-means, means actuating said knitting needles to knit said warp yarn into knit fabric, means to roll up said knit fabric, means guid ing at least one of said warp yarns through a predetermined path, application means to apply a conductive substance to said one warp yarn adjacent said path, detecting means downstream from said application means adjacent said path,-a rodmember rotatably mounted adjacent said path, means on said rod member operably associated with said one warp yarn, means operably associated with said rod member to periodically rotate said rod member and cause said means thereon to depress said yarn onto said application means and said detecting means and control means operably associated with detecting means to automatically adjust the speed of said warp beam when said conductive portion of said one warp yarn lies in said detecting means.

8. The structure of claim 7 wherein said means rotating said rod member includes a solenoid actuator.

9. The structure of claim 8 wherein said warp beam is speeded up by said control means.

10. The structure of claim 8 wherein said conductive substance is an electrolytic salt solution, said detecting means is a sensing grid, said means rotating said rod includes a solenoid actuator and said control means increases the speed of said warp beam when said conductive substance is depressed into said sensing grid.

11. Apparatus to produce a fabric having a warp yarn comprising: a fabric producing machine, means supplying warp yarns to said machine at a constant speed, means to compare one of said warp yarns to a standard length and to detect a warp yarn shorter than said standard length and means responsive to the detection of a warp yarn shorter than a standard length to automatically adjust the speed of said Warp yarn supply means, said means to automatically adjust the speed of the warp yarn including a pair of freely mounted rolls and an endless band around said rolls and means operably associated with said band to detect said difference in length of said warp yarn.

12. The structure of claim 11 wherein said one of said warp yarns is wrapped around at least one of said freely mounted rolls and drives said endless band.

References Cited UNITED STATES PATENTS 2,186,814 1/1940 Adams 66125 2,941,145 6/1960 Roberts.

3,315,159 4/1967 Git-h.

2,298,888 10/ 1942 Kaufmann 6686 2,400,837 5/1946 Nesterowicz 66163 2,423,105 7/1947 Lambach 6686 2,432,518 12/ 1947 Eshleman 66-l25 2,542,331 2/ 195 1 Hiensch 1924O 2,598,540 5/ 1952 Henry.

2,600,256 6/1952 Morrison et al.

2,818,713 1/1958 Porter.

2,820,355 1/1958 Hadfield et al.

2,910,850 11/1959 Held et al.

W. C. REYNOLDS, Primary Examiner US. Cl. X.R. 

